Sorry for the dribs-and drabs posting here, but I just keep thinking of new information that might be useful.
This seems to have been happening since December without me noticing it, actually – I’m basing that on that fact that Wordfence is telling me that the last successful scan was on December 9.
Is there an option to enable Wordfence to email me if a scan failed? (I looked but I might have missed it)
Also, I’ve enabled low resource scanning, no change with that.
I also tried excluding this file, but either I’m specifying it wrong (possible), or it’s forcing a scan because this is a core WP file…?